CN210151718U

CN210151718U - Reinforced concrete base

Info

Publication number: CN210151718U
Application number: CN201920579624.1U
Authority: CN
Inventors: 谭祖彪; 帅海乐
Original assignee: Guizhou China Construction Architecture Research and Design Institute Co Ltd
Current assignee: Guizhou China Construction Architecture Research and Design Institute Co Ltd
Priority date: 2019-04-25
Filing date: 2019-04-25
Publication date: 2020-03-17
Anticipated expiration: 2029-04-25

Abstract

The utility model discloses a reinforced concrete base, which comprises a reinforced concrete base, wherein the reinforced concrete base is in the shape of a cylinder, and the cylinder is provided with a middle hole; the middle hole is a taper hole with a large upper part and a small lower part, the top of the taper hole is provided with an inner inclined plane, the inner inclined plane is provided with a sounding pipe and a grouting hole which are uniformly distributed along the circumference, and a grouting pipe is arranged in the grouting hole; a group of main reinforcements which are radially and uniformly distributed along the circumference are arranged in the reinforced concrete base, and the vertical right-angle sides of the main reinforcements are welded with the spiral stirrups; the bevel edge of the main rib is welded with a group of annular ribs which are uniformly distributed along the axis of the reinforced concrete base. The floating cage can be prevented by the downward force generated by the reinforced concrete base; the bottom surface of the reinforced concrete base is contacted with the bottom surface of the pile hole, and the upward buoyancy generated by the impact of the poured concrete basically has no influence on the bottom section of the pile; the reinforced concrete base has a reinforcing effect on the pile bottom, and the quality of the pile bottom can be improved to a certain extent, so that the quality of the pile bottom can be reliably guaranteed after the pile bottom is secondarily reinforced through the grouting pipe.

Description

Reinforced concrete base

Technical Field

The utility model relates to a reinforced concrete base belongs to construction technical field.

Background

In the process of cast-in-place pile construction, when the bottom of the pile body is positioned in underground water or a slurry retaining wall, the construction quality of the pile foundation is difficult to control. The reason for this is that the ground water or mud at the bottom of the pile has buoyancy to the pile foundation, which is called the floating cage phenomenon. If the cage floating phenomenon occurs in the concrete pouring process, the pile bottom is separated.

In the prior art, a method of grouting the pile bottom or additionally arranging a steel pipe pile at the pile bottom is generally adopted; to prevent floating cage phenomenon. The method mainly adopts the methods of adjusting the specific gravity of the slurry, controlling the slump of concrete, controlling the embedding depth of the guide pipe, accelerating the pouring speed of the concrete or applying a balance weight on the top of the reinforcement cage and the like. The method has the advantages that the effect of controlling the floating cage is not clear, the construction cost is high, the phenomenon of the floating cage of the reinforcement cage cannot be controlled fundamentally, and the pile foundation quality is influenced. Great challenge is brought to the control of the construction working medium quantity of the pile foundation. The prior art solutions are therefore not very ideal.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a reinforced concrete base, when carrying out the construction of major diameter bored concrete pile, can fundamentally control steel reinforcement cage and float the cage phenomenon, improve the quality of pouring of pile foundation to overcome prior art's is not enough.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model discloses a reinforced concrete base, which comprises a reinforced concrete base, wherein the reinforced concrete base is in the shape of a cylinder, and the cylinder is provided with a middle hole; the middle hole is a taper hole with a large upper part and a small lower part, the top of the taper hole is provided with an inner inclined plane, the inner inclined plane is provided with a sounding pipe and a grouting hole which are uniformly distributed along the circumference, and a grouting pipe is arranged in the grouting hole; a group of main ribs which are uniformly distributed along the circumference in a radial shape are arranged in the reinforced concrete base, and the main ribs are in a right-angled triangle shape; the vertical right-angle edge of the main reinforcement is welded with the spiral stirrup; the bevel edge of the main rib is welded with a group of annular ribs which are uniformly distributed along the axis of the reinforced concrete base.

In the reinforced concrete base, the included angle a between the conical surface of the middle hole and the horizontal line is 90-150 degrees.

In the reinforced concrete base, the diameter of the grouting hole is not less than 50 mm.

In the reinforced concrete base, the number of the main reinforcements corresponds to the number of longitudinal reinforcements of the reinforcement cage; the main reinforcement on the reinforced concrete base is correspondingly welded with the longitudinal reinforcement on the reinforcement cage; and the spiral stirrup on the reinforced concrete base is welded with the spiral stirrup on the reinforcement cage.

Since the technical scheme is used, compared with the prior art, the utility model, beneficial effects are as follows: 1. when concrete is poured, downward impact force of the concrete acts on the conical surface and the inner inclined surface of the reinforced concrete base to generate downward force, so that the floating cage can be prevented; 2. the self weight of the reinforced concrete base can offset part of the upper buoyancy, and the reinforced concrete base generates lower pulling force on the reinforcement cage, and the prior art applies counter weight on the top of the reinforcement to generate compressive force on the reinforcement cage, so that the reinforcement cage is easily crushed; 3. because the bottom surface of the reinforced concrete base is contacted with the bottom surface of the pile hole, the upward buoyancy generated by the impact of the poured concrete has no influence on the pile bottom section basically; 4. the grouting holes can prevent the grouting pipes from being damaged in the construction engineering so as to ensure the construction quality of the post grouting process; 5. the triangular reinforcing steel bars in the reinforced concrete base have a reinforcing effect on the pile bottom in the pile bottom range, so that the quality of the pile bottom can be improved to a certain extent; 6. the quality of the pile bottom is reliably guaranteed after the pile bottom is secondarily reinforced through the grouting pipe.

Drawings

Fig. 1 is a schematic structural diagram of the present invention;

fig. 2 is a front view of fig. 1.

The labels in the figures are: 1-a reinforced concrete base; 2-mesopores; 3-inner inclined plane; 4-sounding pipe; 5-grouting holes; 6-grouting pipe; 7-main reinforcement; 8-spiral stirrup; 9-ring rib; 10-a reinforcement cage; 11-longitudinal ribs.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

The utility model is formed by a method for preventing a filling pile from floating cage and is used for the method, as shown in figure 1 and figure 2, the method is that a reinforced concrete base is welded at the bottom of a reinforcement cage of the filling pile, and a middle hole of the reinforced concrete base is arranged in a funnel shape with big top and small bottom; when the pile concrete is poured, the downward pulling force is generated on the reinforced concrete base through the gravity of the concrete so as to prevent the floating cage phenomenon. When the bottom of the steel reinforcement cage is welded with the reinforced concrete base, the reinforced concrete base is subjected to local cooling measures, and concrete cracking of the reinforced concrete base caused by overhigh temperature of the steel reinforcement during welding is prevented. 3 or more than 3 grouting holes are arranged around the reinforced concrete base, grouting pipes are arranged in the grouting holes, and the inner diameters of the grouting pipes are not less than 30 mm. And after the pouring of the cast-in-place pile is completed, the bottom of the cast-in-place pile is reinforced again through the grouting pipe so as to ensure the reliability of the bottom of the cast-in-place pile. The top of the reinforced concrete base is provided with an inner inclined plane to prevent sediment accumulation when the cast-in-place pile is poured and form embedded connection with the pile foundation of the cast-in-place pile. 3 or more than 3 sounding pipes are arranged around the reinforced concrete base, and the concrete pouring quality of the cast-in-place pile is detected through the sounding pipes.

The pouring process of the cast-in-place pile comprises the following steps: the top of a main reinforcement in the reinforced concrete base is welded with the bottom end of a longitudinal reinforcement of a reinforcement cage → the reinforced concrete base is lowered to the bottom surface of a cast-in-place pile hole through the reinforcement cage, and then lifted upwards by 300 mm; inserting a conduit into the bottom surface of the pile hole from the middle hole of the prefabricated reinforced concrete base from top to bottom to clean the gap between the bottom surface of the pile hole and the bottom of the reinforced concrete pile → cleaning, then lowering the bottom of the prefabricated concrete pile to the bottom of the hole again → pouring the concrete of the pile body by adopting a normal concrete underwater pouring process → reinforcing the bottom of the cast-in-place pile by a grouting pipe → detecting the concrete pouring quality of the cast-in-place pile by an acoustic testing pipe → accepting the pile is qualified and submitting an acceptance report to be filed.

The reinforced concrete base of the present invention, which is constructed and used in the above method, as shown in fig. 1 and 2, comprises a reinforced concrete base 1, wherein the reinforced concrete base 1 is in the shape of a cylinder, and the cylinder is provided with a central hole 2; the middle hole 2 is a taper hole with a big top and a small bottom, and the included angle a between the taper surface of the middle hole 2 and the horizontal line is 90-150 degrees. The top of the taper hole is provided with an inner inclined plane 3, the inner inclined plane 3 is provided with a sounding pipe 4 and a grouting hole 5 which are uniformly distributed along the circumference, and the diameter of the grouting hole 5 is not less than 50 mm. A grouting pipe 6 is arranged in the grouting hole 5; a group of main reinforcements 7 which are uniformly distributed in a radial shape along the circumference are arranged in the reinforced concrete base 1, and the number of the main reinforcements 7 corresponds to the number of the longitudinal reinforcements 11 of the reinforcement cage 10; the main ribs 7 are in the shape of right-angled triangles; the vertical right-angle side of the main reinforcement 7 is welded with the spiral stirrup 8; the bevel edge of the main reinforcement 7 is welded with a group of annular reinforcements 9 uniformly distributed along the axis of the reinforced concrete base 1. The main reinforcement 7 on the reinforced concrete base 1 is correspondingly welded with the longitudinal reinforcement 11 on the reinforcement cage 10; and the spiral stirrup 8 on the reinforced concrete base 1 is welded with the spiral stirrup 8 on the reinforcement cage 10.

Examples

This example is shown in fig. 1 and 2, and includes a main reinforcement 7, and the main reinforcement 7 is a hook-shaped reinforcement, and the shape is similar to a right triangle. The number and the diameter of the main reinforcements 7 are the same as the number of the longitudinal reinforcements 11 on the reinforcement cage 10. After the main reinforcement 7 is processed, all the main reinforcements 7 are bound or welded into a whole through the spiral stirrups 8 and the annular reinforcements 9. And (3) erecting a formwork according to the size of the cast-in-place pile between the connected steel bars, installing the sounding pipe 2 and the grouting pipe 6, and then pouring the reinforced concrete base 1, wherein the strength grade of the concrete used by the reinforced concrete base 1 is not lower than C30 and is the larger of the designed strength grade. After the setting period of the reinforced concrete base 1 reaches 28 days, the reinforced concrete base can be connected with the reinforcement cage 10, then the cleaning work of the sediment at the bottom of the pile is carried out, and the construction is carried out according to the normal pile foundation construction sequence.

In the construction process of the cast-in-situ bored pile, the volume weight of the reinforced concrete base 1 and the volume weight of the reinforcement cage 10 are both larger than the volume weight of the slurry retaining wall, and the floating force mainly comprises the buoyancy generated by downward pouring impact of concrete in the concrete pouring process except the buoyancy of the slurry retaining wall. When the reinforced concrete base 1 is adopted, the reinforced concrete base 1 connected with the reinforcement cage 10 firstly descends to the bottom of a hole, then is lifted upwards by 300mm, then a guide pipe is put down to clean the bottom of the pile hole, the reinforced concrete base 1 is descended to the bottom of the pile hole again after sediment at the bottom of the pile hole is cleaned, and then the pile body concrete of the cast-in-place pile is poured by adopting a normal concrete underwater pouring process. When the pile foundation is designed to be an end-bearing pile or a friction end-bearing pile, after the concrete setting period reaches 3 to 7 days, the pile base part is reinforced by adopting a post-grouting process through a grouting pipe 6; when the pile foundation is designed into a friction pile, the pile bottom of the section can be designed into a bearing capacity surplus section, and the treatment can be omitted.

The section of the middle hole 2 of the reinforced concrete base 1 is funnel-shaped, the side surface of the middle hole 2 is a conical surface, the included angle a between the conical surface and the horizontal line can be set to be 90-150 degrees as required, and the top is of an inner inclined surface structure to prevent sediment accumulation and can be connected with a cast-in-place pile foundation in an embedded mode.

The reinforced concrete base 1 is connected with the reinforcement cage 10 by welding or mechanical connection, and local cooling measures should be taken during welding to prevent the damage of concrete caused by overhigh temperature of the reinforcement during welding. The number of the grouting pipes is not less than 3, and the concrete number is determined according to the size of the pile diameter. The reinforced concrete base 1 should reserve grouting holes 5 which have the same number as the grouting pipes 6 and the diameter of not less than 50mm, and the grouting holes 5 can prevent the grouting pipes 6 from being damaged in the construction engineering so as to ensure the construction quality of the post-grouting process.

The utility model discloses a usage under special conditions at the bottom of reinforced concrete precast pile is as follows:

the defects caused by the construction of the large-diameter cast-in-place pile mainly comprise pile bottom concrete segregation, excessive pile bottom sediment and pile bottom defects caused by a steel reinforcement cage floating cage, and workers mainly have the advantages that the three defects are respectively treated on the reinforced concrete prefabricated pile bottom under special construction conditions.

1. Pile bottom concrete segregation

(1) Manual hole digging cast-in-place pile under shallow underground water level

When a building site is located in a shallow underground water level area, the underground water amount is small, and when manual hole digging is adopted, construction is usually carried out by adopting a method of lowering water and digging water while lowering water, the accumulated water at the bottom of a pile is difficult to clean in the water lowering process, the steel reinforcement cage lower cage and the concrete pouring process have inevitable gap time, and the concrete at the bottom of the pile is generally separated due to the accumulated water at the bottom of the hole. If the reinforced concrete precast pile bottom is adopted, the precipitation of the hole bottom part only needs to make the water level lower than the top surface of the precast pile bottom.

(2) High-backfill low-water-level full-casing bored pile construction

When the building site is located the low water level building site of high backfill, the pile length is longer, and pile foundation construction cost is great, and the pile foundation detects to consolidate the degree of difficulty height, and pile foundation concrete quality is more important. Because the water level is low, the underwater pouring process can not be adopted due to the limitation of site conditions, the concrete below the water level is easy to be separated, and the reinforced concrete can be adopted to prefabricate the pile bottom in order to ensure the construction quality of the part of the pile bottom. After the concrete setting period of the pile body reaches 3 to 7 days, the post-grouting process is adopted to reinforce the pile base part, so that the construction quality can be further guaranteed.

(3) Construction of super-large diameter cast-in-place pile

When the building load is large and a cast-in-place pile with an extra-large diameter (the diameter is larger than 2m) has to be adopted, the pile foundation diameter is large due to the limitation of a receiving hopper, the depth of the pile bottom filled with concrete is limited during first pouring, the depth of the embedded pipe is short, the effect of quickly filling the pile bottom cannot be achieved, and the concrete segregation at the pile bottom can be caused due to underground water. When the reinforced concrete precast pile is adopted, the precast concrete pile occupies a part of the pile bottom volume, and the depth of the buried pipe can be increased for the first time due to the adoption of the funnel-shaped precast pile bottom. After the concrete setting period of the pile body reaches 3 to 7 days, the post-grouting process is adopted to reinforce the pile base part, so that the construction quality can be further guaranteed.

2. Pile bottom sediment excessive thickness and steel reinforcement cage float cage

The pile bottom sediment is excessively thick and the steel reinforcement cage floating cage is a pair of spear shield bodies, when steel reinforcements are placed in the cage and secondary hole cleaning is completed, the sediment is controlled by the main method that the pile bottom sediment is discharged by utilizing large reverse impact force during concrete pouring, the discharge of the pile bottom sediment has no effect when the impact force is small, and the steel reinforcement cage floating cage can be caused when the impact force is large. If the reinforced concrete is adopted to prefabricate the pile bottom, the spear shield body can be effectively solved. The solution of the excessive thickness of the sediment at the bottom of the prefabricated reinforced concrete pile and various construction conditions of the steel reinforcement cage floating cage are further described below.

(1) Bored pile with underground water

When the drilling and pore-forming process is adopted, after the drilling is finished, the steel reinforcement cage is placed in the cage and the concrete is waited for, the periphery of the pile is easy to span the hole, and thus the sediment at the bottom of the pile is accumulated.

According to the traditional construction process, if the slurry retaining wall is not adopted, a large hopper is usually adopted for pouring concrete at the moment so as to flush the sediment at the bottom of the pile. In the process, the buoyancy generated by impact is too large, a mud wall protection hole forming process is not adopted, the mud proportion cannot be adjusted, and when the mud proportion is large, a reinforcement cage floats a cage probably, so that the defect of the pile bottom is caused. If the pile bottom is prefabricated by reinforced concrete, the floating cage can be prevented, and the excessive thickness of the sediment at the pile bottom can be prevented. The concrete method comprises the steps of placing a steel reinforcement cage connected with a prefabricated device in a cage, placing a guide pipe to the bottom of a pile, lifting the steel reinforcement cage and the guide pipe before pouring concrete, cleaning sediment at the bottom of the pile by adopting a large amount of clear water, immediately placing the steel reinforcement cage to the bottom, pouring concrete according to a conventional construction method, and further processing the bottom of the pile by adopting a post-grouting process.

(2) Impact hole-forming cast-in-place pile adopting slurry retaining wall

When the requirement on the bearing capacity of a building is large, the depth of a field bearing layer is deep, and a mud dado impact pore-forming construction process is adopted, the upward floating force is large, the upward buoyancy generated by downward impact of concrete in the pile foundation pouring process is large, a steel reinforcement cage floating cage is generated at a high probability, and if the pile bottom is prefabricated by using reinforced concrete, the method and the effect are the same as those of the 'bored pile with underground water'.

When the pile foundation is designed to be an end-bearing pile or a friction end-bearing pile, the base part of the pile is reinforced by adopting a post-grouting process after the concrete setting period reaches 3 to 7 days; when the pile foundation is designed into a friction pile, the pile can be designed into a bearing capacity surplus section without treatment.

The utility model discloses a main advantage as follows:

1. when concrete is poured, downward impact force of the concrete acts on the conical surface and the inner inclined surface of the reinforced concrete base to generate downward force, so that the floating cage can be prevented;

2. the self weight of the reinforced concrete base can offset part of the upper buoyancy, and the reinforced concrete base generates lower pulling force on the reinforcement cage, and the prior art applies counter weight on the top of the reinforcement to generate compressive force on the reinforcement cage, so that the reinforcement cage is easily crushed;

3. because the bottom surface of the reinforced concrete base is contacted with the bottom surface of the pile hole, the upward buoyancy generated by the impact of the poured concrete has no influence on the pile bottom section basically;

4. the grouting holes can prevent the grouting pipes from being damaged in the construction engineering so as to ensure the construction quality of the post grouting process;

5. the triangular reinforcing steel bars in the reinforced concrete base have a reinforcing effect on the pile bottom in the pile bottom range, so that the quality of the pile bottom can be improved to a certain extent;

6. the quality of the pile bottom is reliably guaranteed after the pile bottom is secondarily reinforced through the grouting pipe.

Claims

1. The utility model provides a reinforced concrete base, includes reinforced concrete base (1), its characterized in that: the reinforced concrete base (1) is cylindrical, and a middle hole (2) is formed in the cylinder; the middle hole (2) is a taper hole with a large upper part and a small lower part, the top of the taper hole is provided with an inner inclined plane (3), the inner inclined plane (3) is provided with a sound measuring tube (4) and a grouting hole (5) which are uniformly distributed along the circumference, and a grouting tube (6) is arranged in the grouting hole (5); a group of main ribs (7) which are uniformly distributed in a radial shape along the circumference are arranged in the reinforced concrete base (1), and the shape of each main rib (7) is a right-angled triangle; the vertical right-angle side of the main reinforcement (7) is welded with the spiral stirrup (8); the bevel edge of the main rib (7) is welded with a group of ring ribs (9) which are uniformly distributed along the axis of the reinforced concrete base (1).

2. The reinforced concrete substructure of claim 1, wherein: the included angle (a) between the conical surface of the middle hole (2) and the horizontal line is 90-150 degrees.

3. The reinforced concrete substructure of claim 1, wherein: the diameter of the grouting hole (5) is not less than 50 mm.

4. The reinforced concrete substructure of claim 1, wherein: the number of the main reinforcements (7) corresponds to the number of the longitudinal reinforcements (11) of the reinforcement cage (10); the main reinforcement (7) on the reinforced concrete base (1) is correspondingly welded with the longitudinal reinforcement (11) on the reinforcement cage (10); the spiral stirrup (8) on the reinforced concrete base (1) is welded with the spiral stirrup (8) on the reinforcement cage (10).